Diagnosis
Brush roll drive failure. Primary causes are a broken drive belt, a seized brush roll bearing, or a failed engagement switch.
How to Fix It
Unplug the vacuum. Turn it over. Remove the nozzle plate (two clips). Visually inspect the belt. If it is present and intact, manually try to spin the brush roll. If it does not turn freely, hair is wound around the ends. Cut and remove all wound debris from the bearings at both ends.
If That Didn't Work
The belt may be off its pulleys or broken. Replace the belt. If the brush roll spins freely and the belt is good, the issue is the 'Brush On/Off' switch or its internal wiring. The switch must be in the 'On' position for engagement.
Heads Up
Forcing a seized brush roll can snap the plastic drive pulley. Always clear bearings before reinstalling the belt.